I am getting the following error when executing one one of my LINQ queries
The mapping of CLR type to EDM type is ambiguous because multiple CLR
types match the EDM type 'Product'. Previously found CLR type
'TF.MyProject.DAL.Product, newly found CLR type
'TF.MyProject.DTO.Product'.
The Entity Framework generated class and the DTO object both are under their own namespace. This has worked previously and below is what I have tried so far...
Regenerated the EDMX Model
Removed and Created a new EDMX Model
Run Custom Tool to generate the Template files
Ensure all projects within the solution are using the same Entity Framework version.
Entity Framework version: 6.1.3
Below is how my current project is set up
MyProject
/DAL/MyProjectModel.edmx
/DTO/Product.cs
Any idea or suggestions will be helpful. This has worked in my previous projects with version 6. Not sure if it is specific to a version within release 6..
Note: Moving the DAL to a project of its own resolves the issue
You have two classes with the same name Product. Entity Framework uses Class Names only, irrespective of namespaces or files where it is declared. The error message clearly says you have two Product classes, one in TF.MyProject.DAL namespace and another one in TF.MyProject.DTO.
Try renaming on of these Product classes to some other name and try again.
Related
I have an MVC 5 website with using the entity framework V6.1.1. The entity framework DbContext classes and models were originally all inside the website project. This project had 3 DbContext classes and 3 databases. I had also enabled migrations and applied one one of these databases.
I have now moved all the entity framework classes including the models and the migrations to a separate project and since then I have been getting the following error for the databases where a migration has been applied:
The model backing the 'MyContext' context has changed since the
database was created.
The database has not changed. I have also made sure the Context Key is the same in both the Configuration constructor and the database __MigrationHistory table.
I have also been seeing the following behavior:
I do a Get-Migrations in the package manager console and the correct migrations are returned. Then I am able to build and run the site and no error message is shown until I next make a change and build the solution.
If I change the Context Key in either the database of the Configuration constructor there is no error, but I assume that the migrations are not all being picked up.
I have also been looking through all the migrations files including the designer files and the namespaces all match up. If anyone could shed some light on this problem it would be much appreciated.
You should put this in the constructor of 'MyContext'
> Database.SetInitializer<YourDbContext>(null);
I have created a class library (targeted to .NET 4) containing all my entity framework models/context. I am referencing that class library from one project (targeted to .NET 4.5.1) and it works great, then I am referencing the same class library from another project (targeted to .NET 4) and it gives me this error:
Schema specified is not valid. Errors:
Multiple types with the name 'places' exist in the EdmItemCollection in different namespaces. Convention based mapping requires unique names without regard to namespace in the EdmItemCollection.
And then many more of the same error for all my entities.
You seem to be hitting a type conflict. When resolving types EF does not use namespaces and if it sees two types with the same names it sometimes does not know which one to use. You can find more details in the bug EF team is tracking this issue: https://entityframework.codeplex.com/workitem/483. Also note that as of EF6 most scenarios are fixed when using Code First - see this work item for more details: https://entityframework.codeplex.com/workitem/911
Okay so I just found out I need to downgrade my solution to .NET 4.0. To do this, I upgraded to Entity Framework 6.0 (which is supposed to be .NET 4.0 compatible) and converted all my projects to target the 4.0 framework. When trying to build my data project, the EDMX has several errors. I am unable to open it normally but I can modify the XML data. Here is the error:
The type or namespace name "TABLENAME" could not be found.
I get a bunch of these for several (but not all) tables in my SQL database. Normally, I would do a database update but that does not appear possible here since I can't open the file normally. Additionally, enumerated types that have been defined in the edmx are throwing this error:
The element 'Schema' in namespace 'http://schemas.microsoft.com/ado/2008/09/edm' has invalid child element 'EnumType' in namespace 'http://schemas.microsoft.com/ado/2008/09/edm'. List of possible elements expected: 'Using, Association, CopmlexType, EntityType, Function, EntityContainer' in namespace 'http://schemas.microsoft.com/ado/2008/09/edm' as well as any element in namespace '##other'.
The XML generating this issue:
<EnumType Name="CustomEnum" />
<Member Name="Enum1">
<Member Name="Enum2" />
...
<Member Name="Enum10" />
</EnumType>
I was not the creator of this EDMX file but these enums are essential to the project.
The difference between Entity Framework 4.0 and prior and EF 4.1 and up is huge. The system was moved from 'objectcontext' to 'dbcontext'. If you are just looking to make your solution run and not upgrade to the latest I would recommend deleting all of the .tt files, turning the generation back on for the edmx and just using base EF 4.0.
If you however want to move to the new 6.0 dbcontext paradigm, you may be in for a lot of work redesigning several classes and how they interact with EF.
I created a seperate project and copied over my models to this project.
I referenced
using System.ComponentModel.DataAnnotations
My models are defined like:
public class File
{
[Key]
[Column("file_id")]
public int Id { get; set; }
[Column("user_id")]
public int UserId { get; set; }
...
}
The error I get is:
The type or namespace Column could not be found ...
If I add a reference to EntityFramework it works fine, but I want to re-use my models project by referencing it for my Web Api Rest Client library and don't want to bring in EF for no reason.
I am using .net 4.0
Did they fix this issue (making it loosly coupled with EF) in 4.5?
Yes, this issue is fixed with .NET 4.5.
The Object Catalogue for the EntityFramework.dll of EF 5 with .NET 4.0 (also known as EF 4.4) shows all the attributes in the System.ComponentModel.DataAnnotations and System.ComponentModel.DataAnnotations.Schema namespace that are in the EF assembly:
Whereas the EntityFramework.dll of EF 5 with .NET 4.5 does not contain those namespaces anymore:
The attributes have been moved into the .NET 4.5 framework assembly System.ComponentModel.DataAnnotations.dll under the same namespace they had been before in the EF assembly:
(MinLength and MaxLength are in System.ComponentModel.DataAnnotations as well, the total list of all attributes in there is too long for the screenshot.)
You shouldn't need to reference all of EF. You should just be able to reference System.ComponentModel.DataAnnotations.dll. Adding EF may just add that as a reference for you.
FYI MSDN will tell you which namespace and assembly a framework class exists in.
You don't have to use attributes to create metadata. The whole concept of POCO models is just about it.
The trick is to have an assembly of model classes which do not reference the EF. You can safely reuse this assembly in any context.
Then, in another assembly, you create your DbContext class, refrence the EF and create the metadata programatically. In EF this approach is called Code First Fluent Api.
http://codefirst.codeplex.com/
I have used Entity Framework for DAL in a few projects but in the one I'm working on right now, I have the edmx file in a class library project and that's all there is in the project. I have this project referenced in another class library project and for some reason I'm not able to access any of the entity classes that are defined in the .designer.cs file. I can't access the context class either. If i look at the referenced project in Object viewer in visual studio, it does not list any entities for this project.
Does anyone know why I'm not able to access the entity classes or the datacontext in another project?
EDIT: If it makes any difference, it's associated with a database on sql azure.
This is can happen into two different ways. One is to make sure the Entity Model class are public. The other is to check the Entity Model Namespace is matches to the Context class.
I was able to resolve it by deleting the existing edmx file and regenerating a new one.
Apparently the old one got into a weird state, I was not able to figure out how to get it to work again.
I have used Entity Framework for DAL in a few projects but in the one I'm working on right now, I have the edmx file in a class library project and that's all there is in the project. I have this project referenced in another class library project where i was not able to initialize the object for the entity class saying connection string was not set ,where i have checke with the connection string which was there.\
check your inherited class of DbContext, it must be public
Check the Namespaces of the Context class and Designer.cs class.